|
Contraction |
Definition |
Usage |
|
U |
Intensity unknown (weather reports only) |
NWS |
|
U/S |
unserviceable |
ICAO |
|
UA |
routine PIREP |
ATC |
|
UA |
unable to approve arrival for the time specified |
ATC |
|
UAB |
until advised by |
ATC |
|
UAC |
upper area control center |
ICAO |
|
UAG |
upper atmosphere geophysics |
NWS |
|
UAR |
upper air route |
ICAO |
|
UAT |
until advised by the tower |
ATC |
|
UCDWN |
until cleared down |
ATC |
|
UCLT |
until cleared to land by the tower |
ATC |
|
UD |
unable to approve departure for the time specified |
ATC |
|
UDDF |
up and down drafts |
NWS |
|
UDF |
ultra high frequency direction finding station |
ICAO |
|
UERE |
User Equivalent Range Error |
ATC |
|
UFA |
until further advised |
GEN |
|
UFN |
until further notice |
GEN |
|
UFO |
unidentified flying object |
GEN |
|
UHA |
unable higher altitude |
ATC |
|
UHDODT |
unable higher due opposite direction traffic |
ATC |
|
UHDSDT |
unable higher due same direction traffic |
ATC |
|
UHDT |
unable higher due traffic |
ICAO |
|
UHDT |
unable higher due traffic |
ICAO |
|
UHF |
ultra high frequency |
GEN |
|
UIC |
upper information center |
ICAO |
|
UIR |
upper flight information region |
ICAO |
|
ULDT |
unable lower due traffic |
ATC |
|
ULR |
untra long range |
ICAO |
|
UM |
unable to maintain |
ATC |
|
UN |
unable |
GEN |
|
UNA |
unable |
ICAO |
|
UNAP |
unable to approve |
ICAO |
|
UNAPV |
unable to approve |
GEN |
|
UNAR |
unable to approve altitude requested |
ATC |
|
UNATNDD |
unattended |
GEN |
|
UNAVBL |
unavailable |
GEN |
|
UNCC |
unable to contact company radio |
ATC |
|
UNDLD |
undelivered |
GEN |
|
UNEC |
unnecessary |
GEN |
|
UNHRD |
unheard |
GEN |
|
UNID |
unidentified |
GEN |
|
UNKN |
unknown |
GEN |
|
UNL |
unlimited |
GEN |
|
UNLGTD |
unlighted |
GEN |
|
UNMON |
unable to monitor |
GEN |
|
UNMON |
unmonitored |
ATC |
|
UNOFFL |
unofficial |
GEN |
|
UNRDBL |
unreadable |
GEN |
|
UNREL |
unreliable |
ICAO |
|
UNRELBL |
unreliable |
GEN |
|
UNRR |
unable to approve route requested |
ATC |
|
UNRSTD |
unrestricted |
GEN |
|
UNSATFY |
unsatisfactory |
GEN |
|
UNSBL |
unseasonable |
NWS |
|
UNSKED |
unscheduled |
GEN |
|
UNSTBL |
unstable |
NWS |
|
UNSTDY |
unsteady |
NWS |
|
UNSTL |
unsettle |
NWS |
|
UNTC |
unable to establish contact |
ATC |
|
UNUSBL |
unusable |
GEN |
|
UP |
unknown precipitation |
METAR |
|
UPDFTS |
up drafts |
NWS |
|
UPDT |
update |
NWS |
|
UPR |
upper |
NWS |
|
UPSLP |
upslope |
NWS |
|
UPSTRM |
upstream |
NWS |
|
UQOT |
unquote |
GEN |
|
URAUZ |
you are authorized |
GEN |
|
URG |
urgent |
GEN |
|
URIZR |
your recommendation is requested |
GEN |
|
USA |
U.S. Army |
GEN |
|
USAF |
U.S. Air Force |
GEN |
|
USAFIB |
U.S. Army Aviation Flight Information |
GEN |
|
USBL |
usable |
GEN |
|
USCG |
U.S. Coast Guard |
GEN |
|
USMC |
U.S. Marine Corps |
GEN |
|
USN |
U.S. Navy |
GEN |
|
USNO |
United States Naval Observatory |
ATC |
|
USNOF |
United States NOTAM Office |
GEN |
|
USNS |
United States NOTAM System |
GEN |
|
USP |
urgent special observation (weather reports only) |
NWS |
|
UTA |
upper control area |
ICAO |
|
UTC |
Coordinated Universal Time |
GEN |
|
UTCOK |
Coordinated Universal Time Coordinate Check Completed |
GEN |
|
UUA |
urgent PIREP |
ATC |
|
UVV |
upward vertical velocity |
NWS |
|
UW |
upwind |
ATC |
|
UWNDS |
upper winds |
NWS |